U.S. Pat. No. 4,849,039 discloses a method and apparatus for manufacturing blind material, in which a first layer of the material is applied to the stack supporting means and then a second layer is applied and adhered to the first layer. The stack supporting means 3 (as referred to FIGS. 7 and 8) has a pair of spaced parallel walls 12 which define a space to receive stack 7. At the bottom of each of the walls is a ridge 13 forming a constriction 14 therebetween. The constriction holds a portion of the stack 7 above the constriction and between walls 12. As the weight of the stack increases or under the influence of mechanical forces, the lowest layer is forced through the constriction.
In effect, the portion of the stack 7 above the constriction 14 is so suspended between walls 12 that to be slackened appreciately. In turn, the operation of making the second layer adhered onto the first layer would not be positive and some defects are usually occured.